1. Field of the Invention
The present invention relates to an ink-jet recording apparatus for recording by ejecting ink from a recording means onto a medium to be recorded.
2. Brief Description of the Related Art
Printing apparatuses employing various kinds of printing methods such as a wire-dot method, a thermal method, a thermal transfer method or an ink-jet method have been proposed as mountable print heads to print on printing media (Hereinafter also simply referred as xe2x80x9crecording paperxe2x80x9d) such as paper, cloth, plastic sheets, OHP sheets and the like.
Among these printing apparatuses, a printing apparatus employing the ink-jet printing method (hereinafter also referred as the ink-jet printing apparatus) for ejecting ink and depositing it directly on the recording paper, is a non-impact printing method with low noise, and is capable of performing printings with high density and high quality.
In general, the ink-jet printing apparatus comprises a means for driving a carrier on which the print head is mounted, a feeding means for feeding the recording paper and a control means for controlling aforementioned means.
A piezo-electric element or the like utilizing an electro-mechanical energy converting body, a method of irradiating laser or the like to generate thermal energy for ejecting ink droplets, an electro-thermal energy converting body element having a thermo-resistance body or the like have been known as energy generating elements to generate energy for ejecting ink from ink eject ports of the print head.
Among the above-mentioned print heads, a print head employing the ink-jet printing method for ejecting ink as ink droplets by utilizing thermal energy is capable of printing with high resolution, since ink eject ports can be densely arranged.
Above all, a print head employing the electro-thermal energy converting body element as the energy generating element can be easily reduced in its size with densely packaged structure at low cost by utilizing IC related technologies and micro-fabricating technologies supported by advanced technologies and reliabilities attained in the recent semi-conductor manufacturing field.
As mentioned above, the ink-jet printing method is the quite excellent printing method with a relatively simple arrangement, but still there are problems to be solved.
When the ink-jet recording apparatus has not been used for a long period or when one particular eject port among a plurality of eject ports rarely ejects ink compared with other eject ports, ink ejecting performance is deteriorated owing to ink thickening due to evaporating water in ink around the eject port or an ink chamber communicating to the eject port.
Sometimes ink ejecting directions are deviated, when ink droplets are attracted by deposits derived from such as ink droplets, water droplets or dusts deposited on the eject port surface of the head where eject ports are arranged.
In order to prevent the above-mentioned problems, the so-called eject recovery device equipped in the conventional ink-jet recording apparatus employs the following measures.
As measures for preventing non-eject statuses, the following operations have been employed: a pre-ejection for removing thickened ink or the like by ejecting ink into an ink accepting body before printing; an ink suction for sucking ink from eject ports and a common liquid chamber for removing deposited objects; the ink suction for removing bubbles generated in ink when exchanging ink tanks and a capping measure to prevent water from evaporating out of eject ports.
An ink-jet recording apparatus capable of color printing equipped with the following arrangements has been developed: a plurality of eject port groups for magenta, cyan and yellow inks and the like, except black ink arranged in the same recording head; ink tanks and ink supply systems independently arranged in the respective eject port groups; and a common cap and other eject recovery means for respective groups.
In this type of the recording apparatus, different kinds of inks for black ink and color ink, namely, pigment ink for black ink and dye ink for color ink, have been employed in view of a coloring property for printing in black and of a color reproducibility for printing in color, so that specific caps and suction means for respective pigment ink and dye ink have been arranged in the recording apparatus.
In this case, eject recovery operations for black ink and color ink are respectively executed, and sucked black ink and color ink are discharged from respective discharge openings arranged at different positions.
In FIGS. 18 to 20, positions of discharge pipes of a recovery device equipped in the conventional recording apparatus are schematically illustrated. FIG. 18 is a bottom view of the recovery device schematically illustrating sucked ink discharge openings 54 and 55 for black and color inks. FIG. 19 is a perspective view of the recovery device showing sucked ink discharge openings 54 and 55 respectively formed at tips of suction tubes 32a and 32b for black ink and color ink. Ink discharge openings 54 and 55 are arranged to discharge sucked inks in parallel directions and arranged apart from each other such that discharged black and color inks do not mix each other.
In the conventional recovery device, when particularly black pigment ink is ejected, only black ink is sucked for maintaining eject ports in accordance with a printing frequency, but color dye ink is rarely sucked.
Consequently, the ink discharge opening 54 formed at the tip of the black ink suction tube 32a is occupied by discharged black ink and is finally clogged by the stuck black ink around discharge opening 54 as shown in FIG. 20. A reference numeral xe2x80x9c60xe2x80x9d in the figure is stuck black ink. On the other hand discharged color ink 61 discharged from the color discharge opening 55 does not clog the opening 55.
When the above-mentioned stuck status further develops, the recovery device cannot suck sufficient ink from eject ports, which results in insufficient maintenance statuses in eject ports.
Since pigment ink tends to stick easily compared with dye ink due to its properties, stuck pigment ink discharged from the pigment ink discharge opening deposits around the discharge opening and clogs the discharge opening when stuck pigment ink grows as shown in FIG. 20, which aggravates eject recovery performances. Discharged ink starts sticking to a surface of an ink holding means after it is absorbed by the ink holding means so that the absorptivity of the ink holding means is also deteriorated.
The present invention is carried out in view of the above-mentioned technical problems for providing an ink-jet recording apparatus equipped with an ink eject recovery means capable of stably maintaining the eject recovery performance in normal statuses by discharging dye ink over discharged pigment ink. The recovery means attains the following features: pigment ink is prevented from sticking and depositing; pigment ink is absorbed by the absorbing means more efficiently; and the pigment ink is prevented from clogging around the pigment ink discharge opening.
Objectives of the present invention are attained by providing either one of manufacturing methods of the ink-jet recording head or either one of manufactured recording heads specified in (1) to (8).
(1) An ink-jet recording apparatus comprising: a pigment ink eject portion equipped with pigment ink eject ports for ejecting pigment ink; a dye ink eject portion equipped with dye ink eject ports for ejecting dye ink; a pigment ink recovery means for recovering or maintaining an eject status of pigment ink to be ejected from the pigment ink eject ports; a dye ink recovery means for recovering or maintaining an eject status of dye ink to be ejected from the dye ink eject ports; a discharged ink holding means for holding inks discharged respectively from the pigment ink recovery means and the dye ink recovery means; a discharged pigment ink discharge opening for discharging discharged pigment ink from the pigment ink recovery means to the discharged ink holding means; and a discharged dye ink discharge opening arranged closely to the discharged pigment ink discharge opening, for discharging discharged dye ink from the dye ink recovery means to the discharged ink holding means.
(2) The ink-jet recording apparatus according to (1), where: the pigment ink recovery means comprises a pigment ink cap for capping the pigment ink eject ports and a pigment ink suction means for sucking from the pigment ink eject ports via the pigment ink cap; and the dye ink recovery means comprises a dye ink cap for capping the dye ink eject ports and a dye ink suction means for sucking from the dye ink eject ports via the dye ink cap.
(3) The ink-jet recording apparatus according to (1), where: at least the discharged dye ink discharge opening is arranged apart from the discharged ink holding means.
(4) The ink-jet recording apparatus according to (3), where: the discharged pigment ink discharge opening and the discharged dye ink discharge opening are arranged closely to each other such that mixed discharged ink is absorbed by the discharged ink holding means, after the discharged pigment ink discharged from the discharged pigment ink discharge opening and the discharged dye ink discharged from the discharged dye ink opening are properly mixed.
(5) The ink-jet recording apparatus according to (1), wherein: a recovery operation is executed by the recovery means when the pigment or dye ink eject ports are not in use for a predetermined period.
(6) The ink-jet recording apparatus according to (5), where: the recovery operation by the pigment ink recovery means is executed before the pigment ink starts sticking to the pigment ink eject ports.
(7) The ink-jet recording apparatus according to (1), where: the recording apparatus is equipped with electro-thermal energy converting bodies to generate thermal energy utilized for ejecting ink.
(8) The ink-jet recording apparatus according to (7), where: respective inks are ejected by utilizing film boiling in inks caused by thermal energy generated from the electro-thermal energy converting bodies.